Submitted to: Maternal and Child Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/1/2007
Publication Date: 4/1/2008
Citation: Jing, H., Pivik, R.T., Gilchrist, J.M., Badger, T.M. 2008. No difference indicated in electroencephalographic power spectral analysis in 3- and 6-month-old infants fed soy- or milk-based formula. Maternal and Child Nutrition. 4(2):136-145.
Interpretive Summary: This is a report based on our long-term study that examines the effects of two types of infant formula (milk formula and soy formula) on brain development, brain function, and behavior. Here we are reporting on infants at age 3 and 6 months. We hypothesized that brain function of soy-fed infants would differ from that of milk-fed infants, because soy formula contains some compounds (isoflavones) thought to influence brain development. We found that: 1) in both groups, the development of brain appears more advanced in females than in males at 6 months; and 2) general brain function of both groups of infants were very similar. These are preliminary data, but they suggest that brain development occurs about the same regardless of whether infants are fed the milk- or soy-based formula. Future work should shed more light on these issues as we obtain more data.
Technical Abstract: Increasing concern has been recently raised on the possible effects of soy-derived phytoestrogens on the development of cognitive functions in infants. However, limited studies have been conducted to date, and no data have been made available for determining whether infant soy formula can affect normal development of human brain. We compared EEG spectral power between two groups of infants fed milk-based or soy formula. High-density EEGs of the same 85 infants (46 fed milk-based formula and 39 fed soy formula) were examined at 3 and 6 months of age. The spectral parameters included absolute power, relative power, and spectral edge frequency (SEF) at 85%, 90%, and 95% levels. The frequency domain contained 4 bands (0.1-3, 3-6, 6-9, and 9-12 Hz). EEG signals were collected from 8 brain areas in each hemisphere. The results showed that the highest spectral power was mainly distributed in the low frequency bands and was predominant in the frontal and anterior temporal areas. None of the spectral variables significantly differed between the soy-fed and milk-fed infants (analysis of variance, all p>0.2). However, significant effects were indicated on the SEFs for each of the factors of sex, age, and brain area (all p<0.01). Hemispheric differences in the absolute or relative power were also indicated. Our results suggest that the EEG power spectral development of soy-fed infants does not differ from that of infants fed milk-based formula. In addition, EEG spectral development appears more advanced in female relative to male infants at 6 months.